Merge pull request #237 from mrodrig/235

Add expandNestedObjects option - fixes #235

Author: mrodrig

README.md

@@ -67,6 +67,27 @@ Returns a `Promise` that resolves with the CSV `string` or rejects with an `Erro
   * `excludeKeys` - Array - Specify the keys that should be excluded from the output.
     * Default: `[]`
     * Note: When used with `unwindArrays`, arrays present at excluded key paths will not be unwound.
+  * `expandNestedObjects` - Boolean - Should nested objects be deep-converted to CSV?
+  	* Default: `true`
+  	* Example:
+	```json
+	[
+		{
+      "make": "Nissan",
+      "model": "Murano",
+      "year": 2013,
+      "specifications": {
+        "mileage": 7106,
+        "trim": "S AWD"
+      }
+    }
+	]
+	```
+  	* `true` uses the following keys:
+  		* `['make', 'model', 'year', 'specifications.mileage', 'specifications.trim']`
+  	* `false` uses the following keys:
+  		* `['make', 'model', 'year', 'specifications']`
+    * Note: This may result in CSV output that does not map back exactly to the original JSON.
   * `expandArrayObjects` - Boolean - Should objects in array values be deep-converted to CSV?
   	* Default: `false`
   	* Example:

package-lock.json

@@ -5,7 +5,7 @@
     },
     "name": "json-2-csv",
     "description": "A JSON to CSV and CSV to JSON converter that natively supports sub-documents and auto-generates the CSV heading.",
-    "version": "4.0.1",
+    "version": "4.1.0",
     "homepage": "https://mrodrig.github.io/json-2-csv",
     "repository": {
         "type": "git",

package.json

@@ -27,6 +27,7 @@ export const defaultJson2CsvOptions: DefaultJson2CsvOptions = {
     emptyFieldValue: undefined,
     excelBOM: false,
     excludeKeys: [],
+    expandNestedObjects: true,
     expandArrayObjects: false,
     prependHeader : true,
     preventCsvInjection: false,

src/constants.ts

@@ -12,6 +12,7 @@ export const Json2Csv = function(options: FullJson2CsvOptions) {
         customValueParser = options.parseValue && typeof options.parseValue === 'function' ? options.parseValue : null,
         expandingWithoutUnwinding = options.expandArrayObjects && !options.unwindArrays,
         deeksOptions = {
+            expandNestedObjects: options.expandNestedObjects,
             expandArrayObjects: expandingWithoutUnwinding,
             ignoreEmptyArraysWhenExpanding: expandingWithoutUnwinding,
             escapeNestedDots: true

src/json2csv.ts

@@ -98,6 +98,12 @@ export interface Json2CsvOptions extends SharedConverterOptions {
    */
   emptyFieldValue?: unknown;
 
+  /**
+   *  Should nested objects be deep-converted to CSV
+   *  @default true
+   */
+  expandNestedObjects?: boolean;
+
   /**
    *  Should objects in array values be deep-converted to CSV
    *  @default false

src/types.ts

@@ -47,7 +47,8 @@ const csvFileConfig = [
     {key: 'nestedDotKeysWithArrayExpandedUnwound', file: '../data/csv/nestedDotKeysWithArrayExpandedUnwound.csv'},
     {key: 'emptyColumns', file: '../data/csv/emptyColumns.csv'},
     {key: 'quotedFieldWithNewline', file: '../data/csv/quotedFieldWithNewline.csv'},
-    {key: 'falsyValues', file: '../data/csv/falsyValues.csv'}
+    {key: 'falsyValues', file: '../data/csv/falsyValues.csv'},
+    {key: 'nestedNotUnwoundObjects', file: '../data/csv/nestedNotUnwoundObjects.csv'},
 ];
 
 function readCsvFile(filePath: string) {

test/config/testCsvFilesList.ts

@@ -0,0 +1,3 @@
+level1
+"{""level2"":{""a"":1,""level3"":{""level"":""zero""}}}"
+"{""level2"":{""a"":2,""level3"":{""level"":4}}}"

test/data/csv/nestedNotUnwoundObjects.csv

@@ -616,6 +616,14 @@ export function runTests() {
 
                 assert.equal(csv, expectedCsv);
             });
+
+            it('should respect the expandNestedObjects option being set to false', async () => {
+                const csv = await json2csv(jsonTestData.nested, {
+                    expandNestedObjects: false,
+                });
+
+                assert.equal(csv, csvTestData.nestedNotUnwoundObjects);
+            });
         });
     });